Bad PSU? Makerfarm i3v 12"

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12-28-2015, 08:36 PM
pjfossee

Bad PSU? Makerfarm i3v 12"

I just bought a 12" i3v and am having some issues powering it with a PSU. It's the 12v 30 amp PSU from Amazon. Here's a link:

http://www.amazon.com/Universal-Regu.../dp/B00D7CWSCG

I've wired a power cable to the PSU and when it's on it shows the expected 12v from all of the +v and -v outputs. However, under any load the voltage drops to 2-3v. Even powering just the little fan that comes with the e3d v6 hotend the voltage drops to this level. This voltage drop also occurrs when the PSU is wired to the 5 amp rail on the RAMPS board. The D1 diode is soldered in so that's not the issue. When the PSU is wired to the 11 amp rail however, the voltage does not drop, but I suspect that is because there is no load on that rail. I get these same results with nothing plugged into the RAMPS too. Do you guys have any idea what the issue might be? The PSU is set to 110v as it should be. Let me know if you have any suggestions.

Thanks,

Preston
12-29-2015, 04:17 AM
tonybuckley

Are you saying JUST the fan causes the drop?

If you are measuring the voltage, I assume you have a multimeter and are measuring acrosss the output terminals?

If this is the case, then I can't think of anything else other than a faulty PSU. Assume you have the PSU set to 230v on the little flip switch?
12-29-2015, 11:58 AM
tonybuckley

Quote:

Originally Posted by tonybuckley

Are you saying JUST the fan causes the drop?

If you are measuring the voltage, I assume you have a multimeter and are measuring acrosss the output terminals?

If this is the case, then I can't think of anything else other than a faulty PSU. Assume you have the PSU set to 230v on the little flip switch?

Revision: Is your voltage set to the correct setting for your country - just realised the internet has no boundaries! :-). I've just had one of these turn up today from China but I am happy with my bench supply as it shows volts and amps. I wonder if it works :-)
12-31-2015, 03:52 AM
pjfossee

Thanks for the quick reply. Yes it was just the fan causing the voltage drop and I was using a multimeter to measure across terminals. I got a new ATX PSU from a friend that has a max amp output of 49 amps on the 12V rail. Do you think that'll be enough for the 12" i3v heated bed and other electronics? Based off the numbers it seems like enough to me. It's and EVGA PSU. Thanks.
12-31-2015, 06:06 AM
tonybuckley

Quote:

Originally Posted by pjfossee

Thanks for the quick reply. Yes it was just the fan causing the voltage drop and I was using a multimeter to measure across terminals. I got a new ATX PSU from a friend that has a max amp output of 49 amps on the 12V rail. Do you think that'll be enough for the 12" i3v heated bed and other electronics? Based off the numbers it seems like enough to me. It's and EVGA PSU. Thanks.

Max amp output is often misleading. What's the constant current rating? But I have read the 12" requires 30A max and that sounds plenty. Annoying your LED supply failed.